Heat exchanger pipes. (Source: © Anton / stock.adobe.com)

A device for heat transfer between two thermal exchange mediums. The fluids are separated by a wall through which the heat is transferred. For maximum transfer efficiency, the media need to be in contact for as long as possible and over as large an area as possible, so a heat exchanger often takes the form of a set of tubes through which one of the media flows. Heat exchangers are used in a wide range of industries, such as energy, heating or cooling.